void gris_epsilon_uno_c(unsigned char *src, unsigned char *dst, int h, int w, int src_row_size, int dst_row_size) {
   unsigned char *pixel;       
    unsigned char blue, red, green;   
    unsigned int vMono;   
    int i;
    pixel = src;	   
    int stp = src_row_size * h;
    for(i = 0; i < stp;i = i + 3){
    red = *(pixel+2);
    green = *(pixel+1);
    blue = *(pixel);
    vMono = (red + 2*(green) + blue)/4;	
    if(vMono > 0xFF){ *dst = (unsigned char) 0xFF;}
    else{*dst = (unsigned char)vMono;}
    dst = dst + 1;
    pixel = pixel +3;
    }   
}
